Fluid actuated diaphragm for collet chucks



Dec. 29, 1953 w. G. VON WElSE 2,664,108

FLUID ACTUATED DIAPHRAGM FOR COLLET CHUCKS Filed Feb. 14, 1949Sheets-Sheet l INVENTOR a WILLIAM G. Von WEISE BY r ATTORNEY Dec. 29,1953 w. e. VON WEISE 2,664,108

' FLUID ACTUATED DIAPHRAGM FOR COLLET CHUCKS Filed Feb. 14, 1949Sheets-Sheet 2 FIG. 4.

WILLIAM .6. Von WEISE MW ATTORNEY INVENTOR Patented Dec. 29, 1953 FLUIDACTUATED DIAPHRAGM FOR COLLET CHUCKS William G. von Weisc, St. Louis,Mo.

Application February 14, 1949, Serial No. 76,268

9 Claims.

This invention relates in general to collet chuck actuators and, moreparticularly, to a fluid driven actuator for tightening and releasingcollet chucks and analogous work-holding devices used in machine tools.

In various types of machine tools such as gearhobbin machines,gear-grinding machines, turret lathes, and the like, it is conventionalpractice to mount the work in a collet chuck, or similar device, whichconsists of a split sleeve having a tapering or conical end that fitsinto a seat of corresponding taper so that lengthwise movement of thecollet causes a contraction or expansion of gripping members in whichthe work is held. Frequently, the collet chuck is mounted in some typeof rotating arbor, spindle, or headstock so that the collet and workgripped thereby may be rotated relative to the cutting tool, grinder orhobbing cutter, which is used to form the work.

Quite often during operation collet chucks tend to become wedged tightlyin the seat as the work progresses, and cannot be dislodged by normalmeans. The machine tool operator, after turning a wheel which disengagesthe draw bolt,

work arbor, spindle, or head-stock of a machine i tool for quicklyreleasing and tightening collet chucks or similar work-holding devices,without stoppage of the machine.

It is a further object of the present invention to provide a fluiddriven actuator of the diaphragm type, which is reliable in operationand economical in construction.

It is an additional object of the present invention to provide a fluiddriven actuator having means for readily adjusting the collet chuck orother work-holding device with relation to the spindle whereby thedistance traversed between tightened and released position may beregulated for any particular machine.

It is a further object of this invention to provide a fluid drivenactuator capable of rotating with the work and having a stationarymanifold which does not materially retard the rotation of work-holdingdevice.

It is a further object of this invention to pro- 2 vide a. fluid drivenactuator which will permit the changing of collets of varying sizes in aminimum of time and without'removing the cylinder and draw bolt attachedthereto from the machine.

With the above and other objects in view, my invention resides in thenovel features of form, construction, arrangement, and combination ofparts presently described and pointed out in the claims.

In the accompanying drawings (two sheets) Figure 1 is a fragmentaryperspective view of a collet chuck actuator constructed in accordancewith and embodying the present invention;

Figure 2 is a longitudinal sectional view taken along line 2-2 of Figure1;

Figure 3 is a transverse sectional view taken along line 33 of Figure 2;

Figure 4 is a longitudinal sectional view of a modified type of colletchuck actuator constructed in accordance with and embodying the presentinvention.

Referring now in more detail to the drawings which illustrate practicalembodiments of my invention, l designates the head-stock of a hobbingmachine, gear-cutting machine, or the like, provided with a rotatablespindle 2, operated by conventional means (not shown). said spindle 2 isprovided with an axial bore 3 and is externally threaded on its rearwardor left end (reference being made to Figure 2) for engagement with anadapter collar 4 which is integrally provided with an annular boss 4'and a peripheral flange 5, having Suitable apertures in alignment withregistering apertures in a flange 6 of an adapter collar 1 securedthereto by bolts 8. The collar 1 is provided with an internally threadedcentral aperture 9 axially aligned with, but of larger diameter than,the bore 3 of the spindle 2. In the forward face of the collar 1,concentric with said aperture 9, is an annular recess I!) for snugfitting engagement with the boss 4' of the adapter collar '4. Each ofthe collars 4, I, is suitably provided with radial apertures H, H.respectively, for threadedly receiving set screws l3, M respectively.

Threaded into the aperture 9 is the forward end of a tubular connectingshaft IS the bore of which is axially aligned with the bore 3 of thespindle 2. The central portion of the shaft I5 is relatively thickenedand is provided with a pair of spaced, annular grooves H6, H5 extendinginwardly from its outer surface. Disposed within each of the grooves l6,I6 is a gasket ll of the so-called O-ring type. Located intermediate thegrooves l6, I6 is a shallow annular recess 18 connected by a radialpassage ill with the bore of the shaft [5.

Externally slip-fitted upon the shaft for relative rotation with respectthereto, is a collar 20 having a radially extending passage 2| openingat its inner end into the recess iii of the shaft i5. Suitably securedwithin the passage 2| is a fitting 22 for an air-line 23 connected to asource of compressed air through a conventional twoposition controlvalve having pressure admitting and exhaust positions (the compressedair source and valve not being shown).

The rearward end of the connecting shaft I5. is externally threaded forengagement within an aperture provided centrally in the face of avertically disposed plate 25. having a forwardly projecting annular boss26 abutting surface-wise against the end face of the collar 23. Theplate is turned r arwardly as at a in dished formation and at its marginis formed into an outturned flange 2'! for registration with acorresponding flange 28 on a rear plate 29 of similar configuration asthe plate 25, but having greater depth and an enlarged central aperture33 aligned with the aperture 24 of the plate 25. Disposed between theplates 25, 23 is a membrane or diaphragm 3! fabricated preferably ofrubber or other suitable elastic material, having apertures 1) adjacentits outer margin in alignment with registering apertures 32, 33 providedin the flanges 21, 23 of the plates 29 respectively, for reception ofthreaded bolts 34. The diaphragm 3! thus divides the space within theplates 25, 23 into forward and rearward chambers 35, 35, it being notedthat the chamber 35 is completely enclosed, whereas the chamber 36 isopen to the atmosphere through the aperture 33 of the plate 29.

The diaphragm 3! is centrallv provided with a suitable aperture 31 andis further provided, upon its rearwardly presented face, with aconcentric rigid backing or support plate 38 formed of heavy gauge steelplate and having a central aperture 39 of the same cliametral size as,and in registration with, the diaphragm aperture 31. Upon its forwardlypresented face the diaphragm 3| is provided with a concentric pressurecollar 40 which is also provided with an aperture 4!, having the 821116diametral size as, and in registration with, the apertures 31 and 39,all as best seen in Figure 2 and for purposes presently more fullvappearing.

Threaded-2y mounted in the plate 29 on diametrally opposite sides of theenlarged opening or aperture 33 areguide screws 42 which terminaterearwardly of the backing plate 38. Disposed encirclinglv about andprojecting forwardly from the guide screws 42 are compression springs 43abutting at their rearward ends against the inner face of the plate 23and at their forward ends against the rearwardly presented face of thebacking plate 33, for spring loading the dia phragm 3!.

Slidably mounted in and projecting co-axially from the tubular shaft I5is a driving sleeve 44 which is diametrally turned down at the rearwardend in the provision of an annular abut ment shoulder 35 and adiametrally reduced tail portion d6 which extends snuglv through theapertures 3'1, 39, M and its rearwardlv proiecting end is threaded forreceiving a clamping nut 41.

Provided upon the outer face of the driving sleeve 44 adjacent itsforward end is an annular groove 43 for receiving an annular gasket 49position.

which is somewhat smaller in cross-sectional size than the gaskets ll.Spaced real-wardly of the groove 48 on the outer face of the drivingsleeve 44 is a shallow, relatively wide annular recess 5| opening into arearwardly extending longitudinal recess 5| which, in turn, at itsrearward end opens into the chamber 35. It should be noted that theannular recess 50 is in communication with the radial passage I8 of theshaft I5 for permitting introduction of compressed air or othermotive-power fluid into the chamber 35.

The driving sleeve 44 is internally threaded as at 52 for a shortdistance forwardly from its rearward end and is then counter-bored toprovide an intermediate clearance section 53 and a dlametrally enlargedsecond or forward clearance section 64.. Operatively mounted in therearwardly extending internally threaded portion 52 of the drivingsleeve 44 is an externally threaded adjustment quill which, at itsforward end, projects freely through the clearance portion 53 and. ashort distance into the clearance portion 5!. At its opposite end thequill 55 projects rearwardly and adjacent its extremity is diametrallyreduced and fiatted upon its external face to provide a nut-like endsection 56 positioned outwardly of the aperture or opening 30 so as tobe accessible for gripping with a wrench, pliers, or other similar handtool. Threaded upon the rearwardly projecting end of the quill 55 is alock-nut 5! adapted for locking abutment against the rearwardlypresented end face of the driving sleeve 44. Slidably mounted within andextending through the forward clearance portion 54 is a draw-bar 53projecting at its forward end a short distance into the spindle bore 3and being provided on such forwardly projecting end with an internalconcentric tapped bore 59 for threadedly receiving a draw-bolt whichextends forwardly through the spindle bore 3 and is conventlonallyattached to a collet chuck, or other similar work-holding device notshown). At its opposite end the draw-bar 58 is turned down in theprovision of a shoulder c and a tail portion :1 for loose fittingsiidable d sposition within and through the adjustment quill 55 and atits rearward extremity projects out vardly there beyond and isexternally threaded for receiving a locking nut 6| adapted for abutmentagainst the rearwardly presented end face of the nut-like end section 56of the quill 55.

In operation, a gear blank or similar work piece is placed within acollet or other suitable holding device. By operation of a valve (notshown) in the air line 23 compressed air is admitted into the chamber35, where it exerts a rearward flexing pressure on the diaphragm 3iagainst the pressure of the springs 43. This rearward flexing of thediaphra m 3| causes the draw bar 53 and the draw bolt 60 attachedthereto to be moved commensurately rearwardly pulling the colletrearwardly into locked or work-gripping It will be noted that uponrotation of the spindle 2, the entire collet chuck assembly rotatestherewith, except for the collar member 20, which at all times remainsstationary. To release the collet for removal of finished work, theoperator turns the control valve to exhaust position permitting the airin the chamber 35 to be expelled under force of the springs 43. The drawbar 58 and draw bolt 60 thereupon move forwardly within the spindle 2shifting the collet into so-called work-releasing position.

The relationship of the lon itudinal travel eecomplished by the draw bar58 and draw bolt 60 to the spindle 2, during flexing and return actionof the diaphragm 3i may be adjusted by backing off the lock-nuts 51, 6|to release the draw bar 58 and adjustment quill 55 for longitudinalmovement, and the latter is threaded forwardly or rearwardly, asdesired, within the driving sleeve 44. If, for example, it is desired tohave the draw bar 5% and bolt 60 travel less distance beyond the forwardend of the spindle 2, the adjustment quill 55 is threaded the necessarydistance rearwardly, the nut 51 is tightened, the draw bar 58 is thenpulled rearwardly until the shoulder c abuts against the end face of thequill 55, and then, finally, the nut 61 is tightened. This adjustabilityfeature is of great importance since it permits control over the amountof relative travel between work-holding and work-releasing position,eifecting an economy of time in overall production, as well as providingready adaptability to a variety of machines. It is to be especiallynoted that collet chucks of varying sizes may be utilized as requiredfor any particular operation without removing the draw bolt 60 and drawbar 58 since the collet chucks are merely threaded into the forward endof the draw bolt 66. Thus, it will be seen that this is a markedimprovement over commonly used draw bolt assemblies which, of necessity,have the draw bolt threaded onto the collet chuck.

If desired, a modified type of collet chuck actuator may be providedwhich essentially incorporates a pair of plates 25, 25", substantiallyidentical with the plate 25 above described. The plates 25, 25" aresymmetrically arranged to permit the exertion of pressure on either sideof a diaphragm 3! with attendant advantages as will be shown presently.The diaphragm 3i divides the space between the plates 25, 25" intochambers 35', 35", said diaphragm 3i being pro vided with forward andrearward backing or support plates 38', 33". The plates 25, 25" arethreadedly secured to connecting shafts l5, l5' respectively, which havecollar members 25', 29" disposed concentrically thereabout,respectively, said collar members 29, 20" being connected to air lines23, 23" respectively. Suitably secured to the forward end of the shafti5 is an adapter collar 1 engaged to the spindle adaptor collar 4.Threadedly engaged on the rearward end of the connecting shaft i5 is anend stop collar 62 having a radial aperture 63 for receiving a set screw64, said aperture 66 being provided with a thread protector 55.Extending through the bores of the connecting shafts I5, I 5" andsuitable aligned centrally disposed apertures in the diaphragm 3i andbacking or support plates 38, 38" is an elongated driving sleeve 66having an axial bore 61. Said sleeve 68 is integrally provided centrallywith a collar 58 which is externally threaded for engagement within thecentral apertures of the diaphragm 3i and support plates 35, 38".Adjacent each end of said driving sleeve 56 in the outer face thereof,there is provided an annular groove 69 within which is disposed a gasket10. At its rearward end, the bore 61 of the driving sleeve 66 isthreaded for engagement with an adjustment quill 55' having engagedthereon a lock-nut 51, similar in all respects to the quill 55 andlock-nut 5! respectively, above described. Slidably disposed with in thebore 61 of the sleeve 66 is the forward portion of a draw bar 58',having a shoulder c and a diametrally reduced rearward portion whichprojects through the bore of the quill 55 and is threaded for engagementwith a lock-nut 6!.

The draw bar 58' is provided with a tapped bore 59' in the forward endface thereof for receiving the end of a draw bolt 60.

In operation, air may be admitted into the chamber 35 to effect arearward flexing of the diaphragm 3| with consequent rearward movementof the draw bolt 58', thus moving the collet chuck into work-holdingposition. Upon completion of the operation, air may then be admittedinto the chamber 35" to cause a forward flexing of the diaphragm 3| andthereby move the collet chuck forwardly into work releasing position. Inthe event the collet chuck should, inadvertently, become tightly wedgedin its seat, an increased pressura'as necessary, may be released intothe chamber 3 to dislodge the collet chuck. It is to be noted thatmaximum eiiiciency is effected by this structure since the pressure ofthe air admitted into either chamber is almost completely utilized toflex the diaphragm 3| since such pressure is merely pushing against thenear atmospheric pressure of the other chamber. Thus, the modified typeof collet chuck actuator herein described provides means for positivelymoving the collet chuck into work-holding position and intowork-releasing position. The fixed relationship of the draw bar 58' andthe draw bolt 60' to the diaphragm 3| may be adjusted in the same manneras set forth above in connection with the draw bar 58 and draw bolt toand diaphragm 3|.

If desired, the pneumatic pressure means described above may be replacedby hydraulic pressure means, and it should be understood that othersimilar changes and modifications in the form, construction,arrangement, and combina tion of the several parts of the collet chuckactuator may be made and substituted for those herein shown anddescribed without departing from the nature and principle of myinvention.

Having thus described my invention, what I claim and desire to secure byLetters Patent is:

l. A collet chuck actuator comprising a fire plate member, a secondplate member having a central opening, a flexible diaphragm disposedbetween said plate members and held in engagement with said platemembers at the periphery of said plate members to thereby provide anenclosed chamber and an open chamber, a rigid support platemounted onthe outwardly presented face of the diaphragm, said diaphragm andsupport plate having aligned central apertures in axial alignment withthe opening in the second plate, a driving sleeve extending through saidaligned opening in the diaphragm and support plate, a clamping nutengaged upon the outer projecting end of said driving sleeve in tightabutment against the support plate, said driving sleeve being internallythreaded adjacent its outer end, an adjustment quill threadedly engagedwithin the driving sleeve for selected relative axial positionmentthereto, said quill projecting at its outer end beyond the outer end ofthe driving sleeve, a lock nut engaged upon the projecting end of saidadjustment quill in tight abutment against the end face of the drivingsleeve, a draw bar extending through said driving sleeve and adjustmentquill and projecting beyond the outer end of the adjustment quill saiddraw bar having a diametrally decreased portion providing a shoulder forabutment against the inner end face of the adjustment quill, a lock nutsecured upon the outer end of the draw bar in tight surface abutmentagainst the end face 01 the adjustment quill whereby the draw bar may belongitudinally adjusted with relation to the diaphragm by adjusting therelative positions of the driving sleeve and the adjustment quill, asource of fluid under pressure, and means for admitting fluid into theenclosed chamber for flexing the diaphragm.

2. A collet chuck. etuator comprising a first plate member, a secondplate member having a central opening, a flexible diaphragm disposedbetween said first and second plate members and held in engagement withsaid plate members at the periphery of said plate members to therebyprovide an open and a closed chamber, a rigid support plate mounted onthe outwardly presented face of the diaphragm in tight surface abutmenttherewith, said support plate being of less diameter than the diaphragm,said diaphragm and support plate having aligned central apertures whichare axially aligned with the central opening of the second plate member,a driving sleeve projecting at one of its ends through the centralapertures of the diaphragm and support plate, driving sleeve being ofincreased diameter spacedly from the diaphragm, a pressure collardisposed about said driving sleeve immediately between the increaseddiametral portion thereof and the diaphragmf said driving sleeve beinginternally and externally threaded at its projecting end, a clamping nutengaged upon the projecting end of said driving sleeve in tight abutmentagainst the support plate, an externally threaded adjustment quillengaged within the driving sleeve and projecting outwardly therefrom,the portion of said adjustment quill within the driving s eeve being ofless length than said sleeve, a lock nut engaged upon the projecting endof the adjustment quill in tight engagement against the end face of thedriving sleeve, a draw bar disposed within the driving sleeve and havinga diametrally decreased tail portion for projecting through theadjustment quill, the end face of the diametrally increased portion. ofthe draw bar abutting against the inner end face of the adjustmentquill, a nutengaged upon the projectend of the draw for abutment againsting the end face of the adjustment quill whereby the draw bar beadjusted longitudinally with relation to the diaphragm by the inward orout-ward adjusting movement of the quill, a source of fluid underpressure, and means for admitting fluid into the closed chamber forflexing the diaphragm.

3. A collet chuck actuator comprising a first plate member, a secondplate member having a central opening, a flexible diaphragm disposedbetween said plate members and held in engagement with said platemembers at the periphery of said plate members to thereby provide anenclosed chamber and open chamber, a. rigid support plate rnounte' onthe outwardly presented face of the di said diaphragm and support platemg aligned central apertures in axial alignment with the opening in thesecond plate, a driving sleeve extending through said aligned openingsin the diaphragm and support plate, a clamping nut engaged upon theouter projecting end of said driving sleeve in tight abutment a ainstthe support plate, said driving sleeve being internally threadedadjacent its outer end, an adjustment quill threadedly engaged withinthe driving sleeve and projecting at its outer end beyond the outer endof the driving sleeve, a lock nut engaged upon the projecting end ofsaid adjustment quill in tight abutment against the end face of thedriving sleeve, a draw bar extending through said driving sleeve andadjustment quill and projecting beyond the outer end of the adjustmentquil, said draw bar having a diametrally decreased portion providing ashoulder for abutment against the inner end face of the adjustment quillspring members mounted on the second plate member and bearing freelyagainst the support plate, a source of fluid under pressure, means fordirecting said fluid into the enclosed chamber to flex the diaphragmagainst the counter pressure of the spring members to effect axialmovement of the driving sleeve, adjustment quill, and draw bar, a sourceof fluid under pressure, and means for admitting fluid into the enclosedchamber for flexing the diaphragm.

4. A collet chuck actuator comprising a first plate member, a secondplate member having a central opening, a flexible diaphragm disposedbetween said first and second plate members and held in engagement withsaid plate members at the periphery of said plate members to therebyprovide an open and closed chamber, a rigid support plate mounted on theoutwardly presented face of the diaphragm in tight surface abutmenttherewith, said support plate being of less diameter than the diaphragm,said diaphragm and support plate having aligned central apertures whichare axially aligned with the central opening of the central platemember, a driving sleeve projecting at one of its ends through thecentral apertures of the diaphragm and support plate, said drivingsleeve being of increased diameter spacedly from the diaphragm, apressure collar disposed about said driving sleeve immediately betweenthe increased diametral portion thereof and the diaphragm, said drivingsleeve being internally and externally threaded at its projecting end, aclamping nut engaged upon the projecting end of said driving sleeve intight abutment against the support plate, an externally threadedadjustment quill engaged within the driving sleeve and projeetingoutwardly therefrom, the portion of said adjustment quill within thedriving sleeve being of less length than said sleeve, a lock nut engagedupon the projecting end of the adjustment quill in tight engagementagainst the end face of the driving sleeve, a draw bar disposed withinthe driving sleeve and having a diametrally decreased tail portion forprojecting through the adjustment quill, the end face of the diametrallyincreased portion of the draw bar abutting against the inner end face ofthe adjustment quill, guide screws projecting through said second platemember into the open chamber, sprin members encirclingly disposed aboutthe shanks of said guide screws and abutting freely at their endsagainst the support plate, said guide screws being so spaced as topermit the spring members to exert an evenly distributed pressureagainst the support plate and diaphragm, a source of fluid underpressure, means for directing said fluid into the enclosed chamber flexthe diaphragm against the counter pressure er.- erted by the springmembers for axia1 movement of the draw bar, a source of fluid underpressure. and means for admitting fluid into the enclosed chamber forflexing the diaphragm.

5. A collet chuck actuator comprising a first plate member, a secondplate member, each of said plate members having central openings, a

flexible diaphragm disposed between said plate members and held inengagement with said plate members at the periphery of said platemembers for defining a chamber on either side of said diaphragm, rigidsupport plates mounted on the faces of the diaphragm, said diaphragm andsupport plates having aligned central apertures in axial alignment withthe openings in the first and second plates, a driving sleeve extendingthrough said aligned openings in the diaphragm and support plates, saiddriving sleeve being internally threaded adjacent its outer end, anadjustment quill threadedly engaged within the driving sleeve, a locknut engaged upen the projecting end of said adjustment quill in tightabutment against the end face of the driving sleeve, a draw bar withinsaid driving sleeve and adjustment quill and projecting beyond the outerend of the adjustment quill, a lock nut secured upon the outer end ofthe draw bar in tight sur-- face abutment against the end face of theadjustment quill whereby the draw bar may be longitudinally adjustedwith relation to the diaphragm by adjusting the relative positions ofthe driving sleeve and the adjustment quill, a

source of fluid under pressure, and means for admitting fluid to atleast one chamber.

6. A collet chuck actuator comprising a first plate member, a secondplate member, each of said plate members having central openings, a

flexible diaphragm disposed between said plate members and held inengagement with said plate members at the periphery of said platemembers for defining a chamber on either side of said diaphragm, asupport plate mounted on the faces 4 of the diaphragm, said diaphragmand support plates having aligned central apertures in axial alignmentwith the openings in the first and second plate, a driving sleeveextending through said aligned openings in the diaphragm' and supportplates, said driving sleeve being internally threaded adjacent its outerend, an adjustment quill threadedly engaged within the driving sleeveand projecting outwardly therefrom, the portion of said adjustment quillwithin the driving sleeve being of less length than said sleeve, aclamping nut engaged upon the projecting end of the adjustment quill intight engagement against the end face of the driving sleeve, a draw bardisposed within the driving sleeve and having a diametrally decreasedtail portion for projecting through the adjustment quill, the end faceof the diametrally increased portion of the draw bar abutting againstthe inner end face of the adjustment quill, a nut engaged upon theprojecting end of the draw bar for abutment against the end face of theadjustment quill whereby the draw bar may be adjusted longitudinallywith relation to the diaphragm by the inward or outward adjustingmovement of the quill, a source of fluid under pressure, and means foradmitting fluid to at least one chamber.

7. A collet chuck actuator comprising in combination withchamber-forming members and a flexible diaphragm disposed therebetweenand held in engagement with said chamber-forming members at theperiphery of said chamberforming members, said diaphragm being providedwith a central opening, a driving sleeve extending through the openingin the diaphragm, means for maintaining said driving sleeve in fixedrelation to said diaphragm, said driving sleeve being internallythreaded adjacent its outer projecting end, an adjustment quillthreadedly engageable within the driving sleeve for selected relativeaxial positionment thereto, said quill projecting at its outer endbeyond the outer end of the driving sleeve, means engageable upon theadjustment quill for maintaining same in selected relative position withrespect to the driving sleeve, a drawbar Within said driving sleeve andadjustment quill and projecting beyond the outer end of the adjustmentquill, said drawbar being contoured to provide a surface for abutmentaaginst the inner end face of the adjustment quill, means engageableupon the projecting end of the drawbar for abutment against the outerend face of the adjustment quill, a source of fluid under pressure, andmeans for admitting fluid into at least one of the chambers defined bythe chamber-forming members and the diaphragm.

8. A collet chuck actuator comprising first and second plate members, aflexible diaphragm disposed between said plate members and held inengagement with'said plate members at the periphery of said members, abacking plate mounted on one face of the diaphragm, said diaphragm andbacking plate having aligned apertures, a driving sleeve extendingthrough said aligned openings in the diaphragm and backing plate,locking means engaging on the outer projecting end of the drivingsleeve, said driving sleeve be ing internally threaded adjacent itsouter projecting end, an adjustment quill threadedly engagea'ble withinthe driving sleeve and projecting at its outer end beyond the outer endof said sleeve, locking means engageable upon the projecting end portionof the adjustment quill to maintain same in fixed relation to thedriving sleeve, a drawbar extending through said driving sleeve andadjustment quill and projecting beyond the outer end of the quill, saiddrawbar having a diametrally reduced portion to provide an annularshoulder for abutment against the inner end face of the adjustmentquill, locking means engageable upon the outer end of the drawbar formaintaining the adjustment quill in tight surface abutment against theshoulder of the drawbar whereby the drawbar may be longitudinallyadjusted with relation to the diaphragm by adjusting the relativepositions of the driving sleeve and the adjustment quill, a source offluid under pressure, and means for directing said fluid against atleast one face of said diaphragm for flexing same.

9. A collet chuck actuator comprising a, first plate member, a secondplate member having a central opening, a flexible diaphragm disposedbetween said first and second plate members and held in engagement withsaid plate members at the periphery of said plate members to therebyprovide an open and closed chamber, a backing plate mounted on theoutwardly presented face of the diaphragm, said diaphragm and supportplate having aligned central apertures, a driving sleeve projecting atone of its ends through the central apertures of the diaphragm andbacking plate and into the open chamber, said driving sleeve being ofincreased diameter spacedly from the inwardly presented face of thediaphragm, a pressure collar encirclingly mounted on said driving sleevefor disposition between the diaphragm and the increased diametralportion of the sleeve, said driving sleeve being internally andexternally threaded at its outer projecting end, a clamping memberengaged upon the pro- Jecting end of said driving sleeve for abutmentagainst the backing plate, an externally threaded ad ustment quillengageable within the driv- 11 ing sleeve for projection outwardly atone of its ends beyond the outer end of the sleeve, locking meansengageable upon the projecting end of the adjustment quill formaintaining same in selected position with reference to the drivingsleeve, a drawbar disposed within the driving sleeve for slidingmovement therein, said drawbar being diametrally decreased to form anannular shoulder and a tail portion, said tail portion extending throughthe adjustment quill and projecting at its outer end beyond the outerend thereof, said shoulder abutting against the inner end face of theadjustment quill, a nut engageable upon the projecting end of the tailportion of the drawbar for abutment against the outer end face of theadjustment quill, whereby the drawbar maybe adjusted longitudinally withrelation to the diaphragm by the inward or outward adjusting movement ofthe quill, a source of fluid under pressure, and means for admittingfluid into the closed chamber for flexing the diaphragm.

WM. G. VON WEISE.

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